When extracting multi-phase mixtures, in particular of hydrocarbons, the extraction conditions fluctuate. Hydrocarbons are generally extracted in mixtures, in which different aggregate states are present. In addition to a solid phase, for example sand, liquid phases and gas phases are present. These phases are present in different proportions, wherein the composition of the multi-phase mixtures varies within a wide range so that it is impossible to predict when, and for how long, each composition of the multi-phase mixture will be extracted. Therefore, it may be that, after a relatively long period of extraction with a predominantly liquid phase fraction, a gas phase fraction is extracted for a long period, sometimes until gas phases are extracted exclusively. The moment at which the fractions of a multi-phase mixture will be extracted, as well as the duration of said extraction and the ratio of said proportions, are thus unknown, which hinders the extraction process.
The capital outlay when developing hydrocarbon sources is extraordinarily high. In so doing, it may be necessary to provide a plurality of delivery pumps, for example if the volumes to be conveyed cannot be transported expediently using a particular pump size, for example because the required pump sizes are not available, or because the sizes adapted to the demand are not expedient from a technical or economical point of view.
Young production fields only develop their maximum production after a few years, and therefore there is the problem that a relatively small pump size may be sufficient when extraction is begun, which can lead to problems over the course of further operation however when the pump size suitable at the start is no longer sufficient. There is thus the possibility of operating a plurality of pump units, which are arranged in parallel, so as to provide variability of the delivery rate in addition to a desired redundancy and fail-safe operation. From a logistical point of view, it may be expedient to establish just one pump size and to satisfy the different production demand by means of a different number of parallel multi-phase pumps or by means of a corresponding adaptation of production to the individual multi-phase pumps.
Redundant arrangements of multi-phase pumps reduce the risk of failure, in particular the risk of total failure. In the normal case, the use of speed-variable multi-phase pumps allows wear-reducing operation at reduced speed with a corresponding design, whilst, in the event of failure of a pump, the remaining assembly or the remaining assemblies can largely compensate for the production failure with an increased operating speed.
As mentioned above, when extracting hydrocarbons, the multi-phase mixtures consist of different substances in different aggregate states, for example water, possibly with sand additions, gas condensates, crude oil, natural gas or associated petroleum gas, which have specific weights, which deviate from one another. If multi-phase mixtures are to be divided up among a plurality of multi-phase pumps, there is the problem of ensuring uniform division, since the heavy substances such as liquids preferably fall into exits arranged at the bottom and preferably flow past exits arranged to the side. In the case of branchings, there is thus the problem that a uniform division of the extracted components has to be ensured so as to thus prevent an increased temperature load for pumps charged predominantly with gas fractions.
One possibility for achieving a uniform division of the delivery of the product flow lies in a horizontally, strictly symmetrical arrangement of the distribution points. This has the disadvantage of a high spatial requirement, high weight and associated high costs, and a 2x number of pumps must also always be provided so as to achieve a uniform division. The failure of a pump, arrangement of different pump types, the disconnection of individual pumps or other interruptions leads to non-uniform distributions, which may lead to overloading of individual multi-phase pumps.